The ability to produce large-grain REBCO (RE=Y, Rare Earth) bulk superconductors by melt texturing growth has been improved and refined significantly over the last 20 years. Magnetic bearings, transportation systems, and scientific instrumentation are becoming major innovations of HTS bulk materials. Large grain production is dominated by cold top-seeding melt growth (TSMG). For material optimizing we demonstrate strictly application-oriented fabrication close to the final geometry and thus reducing mechanical machining and assembling work. YBCO hollow cylinder design for journal bearings with radial c axes orientation are obtained by radial-seeding geometry (RSMG). YBCO ring tiles up 120 mm show a perfect cylinder geometry with in-wall a, b orientation and radial c axes. We report improved electric and mechanical bulk properties and demonstrate great production effectiveness. For achieving high field permanent magnets up to 10 T we compare YBCO bulk and ring geometry. Top/bottom double seeded melt growth (DSMG) grain samples provide better magnetic flux trapping capability and show more homogenous properties.

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The General Klectric Company iK engaged in a major program of dovelopin;',, dcsi};ni"S anc ' ni.TniifacLnri.ng a larf;e riiiporconfluct". inft magnet in support of the Large Coil Program, which if; f mid oil by the U.S. Department of Energy aru! directed by the Oak Ridge Nation^] Laboratory. The: oval: ;!i:iped toroidal, in.ignei; vcighs approximately 'VJ7'kH, with hrirc d iamr-.tor;; of 3.35m and 2.35m; and is designed for a maximum magnetic field of 8T at: 30.65 kA. Limi tat ion:; on naf.net weight and available apace for .structural component;; coupled with extremely large magnetic force.. 1 , presented a major challenge in the selection of a mutable structural material. Detailed considerations of de;;ign and fabrication requirements of the coil resulted in the selection of Type 3161,M stainless stc^ol for major structural components. In support of the magnet development effort, an extensive test program was initiated to verify expected base metal properties, to develop weld processes and to establish weld and base metal design allowables. This paper presents the results of the test program which involved testing and evaluation of 25mm thick Type 316LN plate, shielded metal arc weld (SMAK) deposits selected for structural welds, gas tungsten arc t>/e.ld (GTAU) and gas metal arc weld (GMAW) deposits selected for seal welds. The welding development eEfort including measurements of impact properties at RT and 77K; chemical analyses; measurements of magnetic permeabilities and weld ferrite contents, metallographic and radiographic examinations of welds were performed at the Materials and